Due to the increase in data traffic in mobile networks, such as Smart Mobile Broadband (SMBB) networks, optimization of network traffic has become increasingly important. In particular, this applies to downlink traffic which is delivered to clients of a RAN, i.e., User Equipment's (UEs) such as mobile phones, computers, tablet computers, media players, and the like. Such downlink traffic typically comprises data which is delivered from a server providing content, e.g., streamed media, web pages, or software for download, to a client which has request the content. In the present context, traffic optimization, sometimes also referred to as traffic shaping, refers to improving utilization of radio resources, e.g., control signaling and allocation of air interface resources for data transmission between a UE and an access node of the RAN, as well as reducing power consumption in the UE, thereby prolonging UE battery lifetime.
Traffic optimization is typically performed by a network node of a communications network through which a client retrieves content. For instance, traffic optimization may be performed by content providers, i.e., servers, or proxies, such as HyperText Transfer Protocol (HTTP) and Transmission Control Protocol (TCP) proxies, which are used for routing and processing traffic. In the present context, traffic optimization is to be understood to encompass, but is not limited to, pacing, de-pacing, throttling, content compression, video transcoding, video transrating, parental control, and the like. Typically, the type of traffic optimization which is performed is dependent on a type of traffic, i.e., whether the traffic relates to streamed media, software downloads, web browsing, time critical vs. non-time critical traffic, and so forth.
Network nodes performing traffic optimization, such as proxies, maybe placed at different locations in a communications network and may provide different kind of traffic optimization functionality, depending on whether a proxy is located downstream, i.e., close to the RAN or even integrated with the RAN, or upstream, i.e., further away from the RAN.
Proxies which are located close to, or integrated with, the RAN may perform traffic optimization which is based on effecting downswitching of radio states, such as Radio Resource Control (RRC) states in a Universal Mobile Telecommunications System (UMTS), during idle periods of transmission over the RAN air interface. Such traffic optimization functionality, sometimes referred to as radio-friendly pacing, may be based on signaling indications pertaining to idle transmission periods to a control node of the RAN, thereby enabling the RAN to switch to less resource consuming radio states directly at the onset of idle periods rather than in response to an inactivity timer triggering downswitching.
In scenarios where downlink traffic passes through a chain of proxies performing traffic optimization, or where traffic originates at a server performing traffic optimization and subsequently passes a traffic optimization proxy when being delivered to a client, problems may arise when traffic undergoes traffic optimization at several locations.